Self-pivoted blade switch



Nov. 26, 1957 G. L. MOFARLAND SELF-PIVOTED BLADE SWITCH 2 Sheets-Sheet 1 Filed June 24, 1955 IQ n by u tr. e Pa n Twa 0 2|; nM t e. t V A we 4d a; 2 4a, 4 4 P a W C UM. e n: W W 6 b mm 4 b m My 3 F l Nov. 26, 1957 e. L. MOFARLAND 2,814,678

SELF-PIVOTED BLADE SWITCH Filed June 24, 1955 2 Sheets-Sheet 2 Invented: George 1.. McFarland by W is Attorneg.

motors used on automobiles.

United States Patent Ofiice 2,814,678 Patented Nov. 26, 1957 2,814,678 'SELF-PIVOTED BLADE SWITCH *G'e'orge L. McFarland, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application June 24, 1955, Serial No. 517,696

7'Claims. '(Cl. 200-6) applications. In the double-pole, double-throw form the switch unit may be readily mounted for selectively and directlycontrolling the reversing circuits of small electric For example, it may be conveniently mounted under the seat for the finger-tip selective reversing control of the seat adjusting and convertible top raising and lowering electric motors of automobiles.

-In-carrying out the invention in its preferred form a current conducting fiat switch blade is provided with a round headed fiat end that can be readily assembled in current conducting and self-pivoting coplanar nesting relation with a complementary curved opening formed in one of the cooperating flat fixed contacts and then confined'between parallel insulating plates so as to rotatably support the blade in circuit controlling relation with one or more cooperating flat fixed contacts fixedly mounted between the plates.

Such improved coplanar nesting round headed end self-pivoting fiat blade switch structure of the present invention enables the blade and contact parts to be punched directly from metal sheets of uniform thickness and eliminates all need for the usual pivot pins and bearings. Thus the improved switch structure is particularly adapted for low-cost, large-scale production and ready assembly, as well as for long, trouble-free circuit controlling service.

The invention is further carried out by interleaving parallel fiat insulating plates and flat current conducting switch parts provided with mutual interlocking elements to facilitate the ready assembly thereof into a flattened or waferlike switch unit with the movable flat switch blade guided between the plates and the cooperating fiat contacts projecting laterally from the unit to constitute terminals for ready interconnection with a plurality of circuits that are to be selectively controlled by the switch unit.

Further objects and advantages of the present invention will become apparent from the following description of the accompanying drawings in which Fig. 1 is a side view of a manually operable double-pole, double-throw electric switch embodying the self-pivoted round headed end blade structural improvements of the present invention. Fig. 2 is a sectional view of the switch structure shown in Fig. 1 taken on the line 2-4.. Fig. 3 is a side view of the switch structure shown in Fig. 1 taken on the line 33 with certain parts broken away in order more clearly to reveal the inner structural details. Fig. 3 also includes a schematic circuit diagram illustrating the manner in which the double-pole, double-throw switch may be connected for the reversing control of the seat adjusting or top raising motor of an automobile. Fig. 4 shows how a pair of the double-throw, double-pole switches, such as shown in Figs. 1, 2 and 3, may be conveniently mounted in juxtaposition for finger-tip control of the up and down, and forward and back, seat adjusting motors. Fig. 5 shows a modified form of self-pivoted blade switch embodying the improvements of the present invention. Fig. 6 is a sectional view of the modified switch shown in Fig. 5 on the lines 6-6. Fig. 7 is a schematic diagram used in explaining the crisscross contact alignment principle of the modified switch shown in Figs. 5 and 6.

As shown in Figs. 1, 2 and 3, the improved form of self-pivoted blade switch comprises a switch blade 10a in the form of a fiat rectangular strip provided with a round headed end 11. This rounded head 11 is nested within a complementary curved opening 12 formed in the fixed switch contact 13a in coplanar relation. In this way the blade 10a is rotatably supported in circuit controlling relation between the pair of fiat fixed contacts 14a and 14b spaced apart adjacent to the edges of the switch blade 10a. The flat accordionlike springs 15a and 15b engage the opposite edges of the switch blade 16a, to bias the blade to a central position between the fixed contacts 14a and 14b. It will be observed that contacts 14a and 1412 are duplicates. This is also true of the biasing springs 15a and 15b.

The switch parts just described are mounted in edgewise operating alignment between a pair of insulating and clamping plates 16:: and 16b. These plates are provided with suitable interlocking projections for holding the switch parts in proper operating alignment when the insulating and clamping plates 16a and 16b are secured together by means of the cooperating pairs of hollow eyelets 17, 18 and 19. The hollow eyelets 19 preferably are of suflicient diameter to enable the mounting bolts 20 to be inserted therethrough for mounting switch units on the brackets 21, either as a single unit as shown in Figs. 1, 2 and 3, or as a double unit as shown in Fig. 4.

It will be evident that the double-pole, double-throw switch unit shown in Figs. 1, 2 and 3 can be readily assembled simply by interleaving layers of the flat copper punchings constituting the duplicate switch blades 10a, 1%, the duplicate fixed contacts 13a, 13b and the duplicate fixed contacts 14ab-cd along with the biasing springs 15a and 15b in the space between the three duplicate insulating and clamping plates 16a, 16b and 16c as shown in the sectional view of Fig. 2. In such assembly the juxtaposed pairs of fixed contacts 14a, 14b, and Me and 14d are assembled in reversed relationship so that the terminal binding screws 24a, 24b, 24c, and 24d are aligned in offset relation to be readily accessible from the same side of the switch unit as shown in Figs. 1 and 3. Such reversed assembly can be readily accomplished since the notches 25a and 25b are symmetrical with respect to the opening through the contact for the hollow eyelet 18. In order to insulate each of these fixed contacts from the eyelets 18, each eyelet 18 may be surrounded by an insulating bushing 26. Thus it will be seen that the improved switch structure utilizes a minimum number of interlocking duplicate parts especially adapted for lowcost, large-scale manufacture and for ready assembly into either single, double or multiple-pole switch structures as desired.

In the double-pole switch structure shown in Figs. 1, 2, and 3, the duplicate switch blades 10a and 10b may be joined together for operation in unison by means of a suitable spring clip 28. This spring clip 28 is formed to interlock with the slot 29 and the hole 36 punched in alignment in each switch blade.

When two double-pole switch units are mounted in juxtaposition on a common mounting bracket as shown in Fig. 4, each of the spring clips 28 may be provided with a suitable finger-tip operating block 31 formed of a molded plastic, if desired.

As indicated schematically in Fig. 3, the double-pole, double-throw switch may be utilized to control the reversing circuits of a small electric motor, for example, the seat or top raising or lowering motor of an automobile. For this purpose, the operating motor armature 35 has one brush grounded in accordance with standard practice and the other brush connected to the terminal screw 3d of the switch contact 13a which also serves as the terminal for switch contact 1312 as indicated in Fig. 2. The Raise field winding R of the motor also has one terminal grounded and the other connected to the terminal screw 24d. The Lower field winding L of the motor also has one terminal grounded and the other terminal connected to the terminal screw 24a. The battery B in accordance with standard practice has one terminal grounded and :the other terminal connected to each of the fixed contacts 24b and 24c.

Thus, in operation when the two switch blades ll'ila and lilb are raised in unison by means of the spring tip 28 as indicated in Fig. 3, the rounded head 11 readily rotates in the encompassing opening 12 until the upper edge of each blade engages with the corresponding contact Mb and 14d. Thereupon each blade pivots upon the rounded end of the contact 1412 and 14d engaged thereby, thus forcing the rounded head lll into good current conducting relation with :the lower side of the recess 12. This establishes a circuit from the battery B through the conductor 37 to the contact 14b and thence through blade ltla to contact 13a. From contact 13a one circuit extends through conductor 38 and the motor armature 35 to ground, and another circuit extends through terminal screw 36 to contact 13b. From contact 13]) the circuit then extends through switch blade b and contact Md through the Raise motor field winding R to ground. With both the motor armature and the Raise field winding energized, the motor 35 will operate in the Raise direction until the switch blades 10a and Nb are released for return to their midposition in accordance with the bias of spring b.

Upon downward movement of the switch blades 1% and 10b into engagement with contacts 14a and Me respectively, an energizing circuit is extended from the ungrounded terminal of the battery through conductor 39 to terminal 14c and thence through switch blade lldb to contact 13b. One circuit then extends from terminal 36 through conductor 33 and motor armature to ground. The other circuit extends through contact 13a, switch blade 145a, contact Ma and thence through the Lower field winding L to ground. In this case the motor 35 will operate in the reverse direction until :the switch blades 10a and 10!) are released for return to their midposition in accordance with the bias of spring 15a.

In the modified double-throw, double-pole pivoted blade switch construction shown in Figs. 5 and 6, only a single switch blade 10 is required. This blade 1th is provided with a round headed end 11, the same as shown in Figs. 1, 2 and 3. In this case the round headed end ill is encompassed within a complementary curved opening 12 formed in the fixed switch contact 13. The switch blade 19 is provided with a pair of duplicate rocker contact members 41 and 42 pivotally mounted on the pins 43 and 44. The rocker contacts 41 and 42 are thus supported in symmetrical straddling relation with the opposite edges of blade 10 by means of the spacers and 46 as shown in Fig. 6.

Two pairs of duplicate contacts 50a, 50b, 50c and Stid ell) are spaced apart on opposite sides of blade lit to be engaged by the rocker contacts 41 and 42, respectively. Each of these contacts is provided with an offset terminal screw and with the interlocking notches 25a and 25b so that the duplicate contacts can be assembled in reverse relation with the binding screws in offset relation to be readily accessible from the same side of the switch unit as indicated in Fig. 5. Each of the fixed contacts 50a, b, c, d is provided with a projection 51 ottset on the same side of the contact as the terminal screw as shown in Fig. 5.

The switch parts just described are mounted in operating alignment between a pair of duplicate insulating and clamping plates 52 and 53. These plates are provided with suitable interlocking means for engaging with the notches 25a and 25b when the plates are clamped to gether by means of the cooperating pairs of hollow eyelets 17, 13 and 19, the same as shown in Figs. 1, 2 and 3. The two pairs of juxtaposed contacts 5tlab and 5t)cd are maintained in parallel spaced apart relation by means of the flat insulating washers 54 and 55, as well as the insulating bushings 56 and 57 that surround the hollow eyelets F18. The springs 58 and 59 and also the contact 13 are assembled centrally between the plates 52 and 53 so as to be maintained in operative relation with the switch blade lit, when the eyelets are headed over to form the switch unit.

Thus, in operation when the switch blade 10 is raised, the rocker contact 42 is carried into self-aligning engagement with the reversed offset projecting tips 51 of the contacts 54% and 56d. This causes the switch blade to pivot on pin 43 to increase the contact pressure between the headed end 11 and the encompassing opening 12. With the same motor armature, field and battery connections shown in Fig. 3, the modified form of switch shown in Pig. 5 will produce the same direction of rotation of the motor when the blade it is raised. Likewise when the blade 10 is lowered, rocker contact 41 is carried into selfaligning engagement with the projecting contact tips 51 of the pair of contacts 5% and 5%. With the same connections shown in Fig. 3, the direction of motor rotation will be reversed.

Fig. 7 schematically shows the improved crisscross contact alignment principle of the modified form of switch shown in Figs. 5 and 6. As indicated in Fig. '7, the projecting contact tips 51 of the pair of contacts 500 and 50d and of the pair of contacts Slia and 5d,) are in spaced apart crisscross alignment with the blade 10 as indicated by the dotted lines X and Y. As a result the blade ll) will carry the rocker contact Ai-Z to engage the diagonally opposite corners thereof with the projecting tips 5'1 that project from the diagonally ottset corners of the contacts 500 and 5%. In the same way the blade it? will carry the rocker contact 41 to engage the diagonally opposite corners thereof with the tips 51 that project from the diagonally opposite corners of the fixed contacts fit-a and 50!).

While I have described by way of illustration preferred embodiments of my invention, many modifications will occur to those skilled in the art and i, therefore, wish to have it understood that I intend in the appended claims to cover all such forms and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric circuit controlling switch having in combination a fiat switch blade provided with a flat round headed current conducting end, and parallel insulating plates having a first flat contact and a second fiat contact mounted in predetermined spaced relation therebetween and having the second contact provided with a complementary curved opening for coplanar nesting the round headed current conducting end of the blade to rotatably support the blade in circuit controlling relation with the first contact.

2. A switch structure having in combination a fiat switch blade provided with a round headed current conducting end, a first fiat fixed contact, a second fiat contact provided with a complementary curved opening for coplanar nesting the flat round headed end of the blade to pivotally support the blade, and a pair of insulating and clamping plates provided with interlocking means for mounting the flat fixed contacts and the flat blade in operating alignment therebetween.

3. A selective circuit controlling switch having in combination parallel insulating plates having current conducting parts extending therebetween and including a flat switch blade provided with a fiat round headed current conducting end and having an operating connection at the outer end, a pair of flat fixed contacts spaced apart on opposite sides of the blade adjacent the round headed end, and a third flat fixed contact offset from the spaced apart pair of contacts and provided with a complementary curved opening therebetween for coplanar nesting the round headed end of the blade to substantially increase the contact pressure between the round headed end of the blade and the third contact when the blade engages either of the pair of fixed contacts.

4. A selective circuit controlling switch having in combination current conducting parts of uniform thickness including a flat switch blade provided with a fiat round headed end, a pair of flat fixed contacts in spaced apart alignment with the edges of the blade, and a third fiat fixed contact provided with a complementary curved opening for coplanar nesting the round headed end of the blade to rotatably support the blade for circuit closing engagement with either of the pair of contacts, and a pair of insulating and clamping plates provided with interlocking means for mounting therebetween the fixed contacts in edgewise spaced apart alignment and the blade in edgewise operating alignment with the fixed contacts.

5. A double-throw electric switch having in combination parallel insulating plates having current conducting parts extending therebetween and including two pairs of juxtaposed flat fixed contacts in edgewise spaced apart alignment, a blade provided with a round headed end, and a fifth flat contact in edgewise offset alignment with the pairs of fixed contacts and provided with a complementary curved opening for coplanar nesting the round headed end of the blade to pivotally support the blade for selective circuit closing engagement with either of the juxtaposed pairs of fixed contacts.

6. A double-throw electric switch having in combination, a pair of spaced apart insulating plates having current conducting parts extending therebetween and including a blade having a round headed end, a pair of rocker contacts pivotally mounted on opposite edges of the blade adjacent the round headed end, two pairs of fixed contacts having tips in spaced apart crisscross alignment with the rocker contacts, and a fifth contact provided with a complementary curved opening for coplanar nesting the round headed end of the blade to pivotally support the blade for selective circuit closing engagement of each of the rocker contacts with the tips of the corresponding pair of fixed contacts.

7. A double-throw electric switch having in combination, a pair of spaced apart insulating plates having current conducting parts extending therebetween and including two pairs of juxtaposed flat fixed contacts in edgewise spaced apart alignment and each pair having contact tips projecting from diagonally opposite corners thereof, a blade having a round headed end and provided with rocker contacts pivotally mounted on opposite edges thereof adjacent the round headed end, and a fifth flat contact in edgewise offset alignment with the pairs of fixed contacts and provided with a complementary curved opening for coplanar nesting the round headed end of the blade to pivotally support the blade for selective circuit closing engagement of diagonally opposite corners of each rocker contact with the contact tips of the corresponding fixed contacts.

References Cited in the file of this patent UNITED STATES PATENTS 599,553 Dunderdale Feb. 22, 1898 1,434,217 Ledwidge Oct. 31, 1922 1,497,241 MacGonigal June 10, 1924 

